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sion strange conflicts and seditions in the air: and,were our senses fine enough to discerne the invisible commotions of the atmosphere, we should ■ee it oftentimes disturb'd and fluctuating, no lesse then the most tempestuous seas.

They are not alike terrible in all places between the tropiques, but raign more especially near high shoars and islands that lye to the eastward from the Continent; so that they infest the Philippine and Caribbe Isles, more then any other parts of the habitable world.

Nearer the Line its most inclin'd to calmes; and though in the torrid zone, there is but one set wind all the year round, yet they are also extremely subject to tempests, whenever the Levants encounter any opposition from the west. For although (as I before noted) the progresse of wind is naturally direct, yet meeting with any impediment, it whirles about in a circular and vortiginous motion. This cause was assign'd by Dorisi of the dangerous storms that happen near the equinoctiall, and (not to instance in severall others, who have declar'd for the same hypothesis) Riccinlus, and more expresly Varenius, in his geography, gives the like account of these typhons, or hurricanes:

"Causa typhonis procul dubio est, quod ventus ex aliqua plaga erumpens, versus aliam, in hac reperit impedimeutum, &c. Potest etiam esse ab oppositis ventis simul spirantibus, &c."

We see these kind of eddys in rivers, when the course is stopt by a dam or bank, at least when two contrary currents meet. And I believe the phenomenon of hurricanes might be sufficiently illustrated from hydrostatique experiments, were it not my intention rather to prosecute their natural history, then to determine their cause. Though I shall endeavour to collect such observations, as may not obscurely hint to us the fittest materials, on which to superstruct an hypothesis. But we cannot safely adventure upon this arduous attempt, without more exact discoveries of many particular circumstances, and accidents, which are of greatest importance to these nice speculations.

I should enquire what anniversary winds blow either in Guiana, or the neighbouring continent, especially from the west, in those months which are most suspected for hurricanes.

Then, what judgment can be made of their causes, from their prognostiques, since I am assur'd from very good hands, that they have oftentimes been foretold by the Indians. Moreover the influences of the sun, the nature of the currents and shoars, the phasis of the moon, &c, ought not to be neglected by the inquisitive naturallist.

Lastly, whether they are not frequently accompany'd by earthquakes, as I have been inform'd by some who were planters in the West Indies, which was likewise taken notice of in that excellent history of the Caribbes, of an hurricane which happen'd in the year 1563, together with an earthquake. For the included spirit, which caus'd that palpitation in the bosome of the earth, being afterwards releast from its imprisonment, might occasion these dreadfull tempests and winds. Fournier (who is generally reputed an author of good credit, and skilfull in what relates to hydrography) mentions an innundalion on the coasts of America, an eruption of a burning mountain, and an earthquake neer the same time; which for the meraorableness of the event, I shall set down in a few lines.

Thirty-five leagues on the south of Lima, is situate a famous port call'd Hisco; and a town in which most of noblesse and persons of qualitie doe reside; who perceiving one day,that the sea retir'd all at once from their shoars, and left the river dry, great numbers of people flock't together on the shoare, to behold so extraordinary a sight; little uspecting the ill destiny which was to attend them : for presently after hey saw a great and suddain tumour of the sea, and perceiv'd the water to boyl, and the waves to swell, and rowle one upon another; not like waves, but mountains of water, so high, that there remain'd no hope of saving their lives by flight; expecting every moment when they should he swallow'd up by the sea: So that, the ocean quitting its ordinary hounds, made an excursion for three hundred leagues; overlurn'd the houses and trees, and left the country desolate; the ships saly'd over the highest walls, during this wonderfull intimidation. Canama, a noted village distant two hundred and thirty leagues from Lima, was destroy'd with its port, and many other places; more especially the town of Arica, which lost in the harbour many ships richly laden, to the value of a million in gold. The mountain Onerate, which, some years since, had vomited out a great quantity of ashes, began a very terrible conflagration, and was followed by a suddain trembling of the earth, which in less than a quarter of an houre, swallow'd up severall villages; that there was scarce ever a more dreadfull earthquake.

It is not unusual 1 to have innundation of the seas, eruptions of burning mountains, earthquakes, and then violent tempests, like hurricanes, to happen about the same time, and probably from the same cause: For the nitro-sulphureous spirit which causes the trembling of the earth, and that stupenduous commotion of the seas, may afterward break loose into the most horrid conflagrations and winds; especially in such places that abound with these thundring minerals; which, if we consider their active nature, are the fittest materials for hurricanes. I know not how farre it may be thought a confirmation of this, that Braybrook in Northamptonshire, where (as was at large describ'd in the last of the Philosophical Transactions,) there happen'd that dangerous whirlewind the last year, has been a place much subject to earthquakes. But I return from this digression to the hurricanes of the West Indies, where it seems to me very odd, that they should be so dreadfull in some places of the Caribbe Islands, insomuch that Mevis and St. Christophers have severall times been almost depopulated by them, when they never reach to Jamaica, on the one side, (hapily as lying without the vortex of the whirlewind,) nor on the other, beyond Barbados, where they have seldome more then the tail of an hurricane, though it is not farre situate from St. Christophers, Porto Rico, Gardaloupe, and other islands, where they rage with the greatest violence.

They are no strangers to the Moluccas and Philippines, and we have most incredible relations of the stormes in the way to Japan, which hare carry'd ships a considerable distance from the sea, up the dry land: some have been miserably wreck't, and bury'd in the waves, others split in a thousand pieces against the rocks, that scarce one ship in five escapes these disasters in the tempestuous months about autumn, or at the change of the monsoons. From hence we may collect this considerable remarque. That they never happen but oil the eastern -shoais, where they are fatal to the Chinese and Caribbe seas, and so farre as the River of Plate; likewise to that part of Africk from the Cape to St. Lawrence,* and the adjacent isles: when they are altogether unknown to the African Ocean, from the Canaries to Cape Bon Esperance, are never heard of at New Spain, or the coasts of Peru, nor towards any other western parts of America; because there the winds, which blow off from land, make no opposition against the generall brise, but comply with the constant motion of the air between the tropiques, from east to west: For the shifting of the trade wind from the easterly points, is usually the first onset of an approaching hurricane.

Yet, however these suspicions of mine be receiv'd, I think it cannot he rationally disputed, but that those direfull tempests have their first from the western continent, for we seldome encounter them very remote from land, and the experienc'd masters of ships are never jealous of hurricanes in the spacious ocean; or, if they perceive them coming, immediately make, out to sea, where their fury is much lesse, then neeir the shoars.

They are the most to be dreaded about the end of summer, in the months of July and August; for both winds and seas, imitate the motions of the sun, and being dilated by the Celestiall heat, annually revert from north to south; and from south to north again; so that the sun hasting from one tropique to another, causes the like suddain conversions in the currents and winds; and being the most universall efficient, must needs be principally concern'd in all vicissitudes of the sublunary world.

(To be concluded in our next.)

Australian Navigation.Mordaunts Shoal, at the entrance of Bloomfields Rivulet.Australia, Eastern coast

This shoal is not laid down in any of the charts, and is very dangerous for ships running into. Weary Bay, particularly during the night, or any other time after sunset. It is of small extent, not more than half a ship's length over, and nearly dries at low water, at which time it slighty breaks; it is composed of hard sand, and the vessel struck heavily on it, and had it not been for the assistance of the other ships she must have sustained much greater damage. I made the position of the shoal to be in latitude 15° 54' south, and longitude 145° 22' east, by chronometer corrected at Fitzroy Island. The channel between the sand and the shore is quite clear, and a ship may run in within threequarters of a mile of the shore, carrying four and a half, and four fathoms. The shoal bears from the entrance of Bloomfields Rivulet N.E.b.E. off shore about two, or two and a half miles. Should a ship be steering for the bay from the southward, by paying strict attention to the lead, will receive notice of the approach towards it, having passed Cape Tribulation at the distance of two, or two and a half miles. If the sounding decrease to nine fathoms, and then quickly to seven, and six and a half, she should haul in for the shore, and run along it at the distance of about one mile in four or four and a half fathoms, rr if dark, it would ^e prudent to anchor immediately. I observed this

* Now called Madagascar.

shoal last voyage, when weighing from the northern part of the bay, in company with her Majesty's brig Britomart, hat as Captain Stanley and officers contended that it was not a shoal, I concluded that 1 was mistaken.

N.B.—But it is now evident that this is the same that I saw before, and being a new discovery, I have named it Mordaunts Shoal.

Two shoals bearing east from north 8°, showing brown, and not very plain until very close:—we were forced to haul very quick to the eastward to clear them.

J. MoRDAl'KT.

An extract from Captain MordaunCs log, of the ship Canton. "At Hi, 30m. abreast of Cape Tribulation: at 5h. 30m. shortened sail and ran for Weary Bay: at 6 suddenly shoaled our water to nine fathoms, eight, seven, and six and a half, decreasing rapidly; rounded to and brought up with the bower in six fathoms,—the Robert Henderson immediately rounded to and brought up likewise, about half a cable's length to the southward and westward of us. The Bencoolen, in giving us a berth of about a cable s length, grounded on a sandbank to the eastward of us, and remained fast,—immediately lowered the cutter, and went with eight hands to assist in getting her off: got ■ hawser from the Robert Henderson, and also run out a stream anchor, and hove a heavy strain, the Robert Henderson having taken her hawser to their windlass. After letting go their second anchor, for fear of their first coming home, at nine sent the remainder of the crew to assist in heaving her off; about lOh. 20m. got her afloat, and anchored her in six fathoms ahead of us, but not before she had knocked her rudder off, having broke four of the pintles."

New Reefs And IslandsAustralia.

9, Upper Park Street, Greenwich, Oct. 5th, 1840. Sept. 2lsl, 1836.—At 6 A.m. weighed with a moderate breeze fro* JJ.E. by eastward, and stood for the eastern side of the large Palm Island. Mount Hinchinbrook, (which has a rugged summit and several peaks,) visible from the deck. At 8 A.m. this mountain bore N.W.b.W.—Palm Island No. 2, W.S.W. Ran to the northward along the group of tb* Palms.at the distance of four or five miles, and at lib. 30m. A.m., discoloured water was seen about one-third of a mile on the starboard bow, —altered course to clear it, and passed one-third of a mile from as (apparently) shoal patch of coral. When its extremes bore E.N.E. and N.li.K., and the vessel was one-third of a mile from the body of the •hoal; the following bearings were taken with an azimuth compass:— South-east point of the large Palm Island S.S.E. } E. easterly, (magnetic.) North-west point of ditto . . 81 W."

Northward peak of Mt. Hinchinbrook N.W.b.W. J W. westerly"

From the masthead it appeared to be three-quarters of a mile in length, north-west and south-east, and one and a half cables in breadth at its centre, narrowing towards each end. One cable s length to the eastward of it are two small round patches, with deep water between them and the large shoal!

The bearings given above, with the variation marked in the chart, will place the bank a little distance outside Captain King's tracks, I think; for having no chart by me, and four years having elapsed since I marked it in the "Zebra's," I cannot speak with certainty. Some miles to the eastward of it, and in about the same latitude, a reef is placed, (marked PD,) on which the San Antonio struck. In a book of directions by Captain King, which I procured at Sydney, it is stated, that she struck during the night. I think it possible from this circumstance, the reef seen by us may be the one she got on. The bearings may be relied on,—although not specified in degrees, &c, as I was most particular in taking them.

Relative to the second reef seen by us to the westward of Booby Island, I find the following remarks. October 11th, 1836.—At 6 A.m. Booby Island E. J S. five miles; at 7 A.m. it bore E.b.N. twelve miles. Steered as follows,—W.S.W. 6-2 miles; W.b.S. \ S . thirteen miles, till 10 A.m., at which time, discoloured water was observed three points on the larboard bow, one mile and a half distant, extending in an east and west direction about one mile, and about an eighth of a mile in breadth. The east and west extremes appeared to have the least water on them. The " Zebra" passed aboat a mile and a half to the northward of it, and its outline was distinctly seen from the masthead:—its position was ascertained as follows:—

[table]

The variation by amplitude in the evening, with the brig's head W.b.N. \ N. was 1° 22' east, which has been allowed in correcting the courses, &c.

This reef is some miles to the southward of Flinders track, and I could not help remarking, that the soundings obtained by him immediately to the northward of this position, are less than they are a few miles to the eastward and westward, as if a sub-marine ridge existed running north and south, and approaching the surface at the spot seen by us.

In the Nautical Magazine for August, 1840, (p. 538,) I see mention made of a rocky islet, which is not laid down in the chart. The same islet was seen by us in the " Zebra," and as evening was approaching, we anchored in consequence. Perhaps the following extract from my remark-book, may enable you to give it an approximate place.

September \blh, 1836, 5h. 30m. P.m—Observed a small rocky islet on with Cumberland Island, [li] which does not appear to be laid down in the chart. Came to in twenty fathoms stiff clay, the following islands visible from deck.

[ k I ] (peak,) north 79° east,—[k] (sloping gradually,) centre north 59° 45^ east.

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